Various configurations and models of liquid dispensers, particularly liquid soap dispensers, are well known in the art. Conventional dispensers typically employed in public restrooms and the like are wall-mounted units that typically include a housing or structure that contains the liquid to be dispensed. The dispensers typically include a delivery device, such as a dosing pump, and a device such as a lever or button for actuating the dosing pump.
Many dispensers have a vent valve. The vent valve serves to allow air to enter the reservoir as the liquid in the reservoir is dispensed. When the differential pressure between the inside and outside of the dispenser reaches a prescribed level, the vent valve opens and allows air to enter and replace the liquid that was dispensed. The opening in the dispenser through which the air flows is desirably small so as to be inconspicuous and help prevent leaks. Therefore it often takes an undesirably high pressure differential to activate the vent. There is therefore a need for a vent that activates at reduced pressure differentials.
Additionally, because many dispensers are single use dispensers that are discarded when empty, the components of the dispensers are often produced from inexpensive plastics. The plastic parts can often warp or deform to the point that the sealing ability of the vent becomes deficient. Therefore, there is a need for a vent that provides improved sealing capability.
The present invention is an improvement over existing systems in that it provides a disposable self-contained dispenser that is activated at reduced pressure differentials between the inside and outside of the dispenser. The present invention also provides a disposable self-contained dispenser having a vent that provides improved and redundant sealing capability.